Artificial Seawater Models Affect Sorption of Adenine and Related Molecules Sorption onto Montmorillonite: Implications for Early Mars and Earth Oceans.

The adsorption of biomolecules onto mineral surfaces plays a crucial role in the context of prebiotic chemistry, as originally proposed by John Desmond Bernal. According to Bernal's hypothesis, clay minerals could have facilitated the concentration and stabilization of organic molecules, creating favorable microenvironments for prebiotic reactions and polymerization processes. In this study, we evaluate the adsorption behavior of adenine, adenosine, and adenosine monophosphate (AMP) onto montmorillonite under different artificial seawater conditions, simulating early Earth and early Mars aqueous environments. The adsorption efficiency varied depending on the ionic composition of the solution, with AMP exhibiting the highest adsorption, likely due to its phosphate group interacting with divalent cations in solution and clay surfaces. These findings suggest that montmorillonite could have played a significant role in the retention of organic molecules under prebiotic conditions. In particular, these results reinforce the idea that early oceans, lakes, or hydrothermal systems with high mineral content might have acted as selective reservoirs for prebiotic compounds. These insights contribute to our understanding of how prebiotic chemistry could have evolved in different planetary scenarios, with implications for the origin of life on Earth and potentially on Mars.